The present invention relates to apparatus for shifting the magnetic tape head of cartridge type multitrack tape player. More particularly, the invention relates to apparatus for shifting the magnetic tape head of a multitrack tape player, which apparatus shifts the tape head via a driving force of the capstan flywheel of the tape player.
In a tape player using multitrack tape, several types of signal information are recorded and reproduced by shifting the magnetic tape head from a specific position to another position. In order to shift the magnetic head, a cam device having plurality of cam surfaces is used and the magnetic tape head shifts vertically as a result of tracing on the rotating cam surface. A known technique for driving the cam device in apparatus using a solenoid is disclosed, for example, in U.S. Pat. No. 3,437,762 to Lear and a known technique for using a driving force of the capstan flywheel is disclosed in U.S. Pat. No. 3,839,732 to Bachmann.
However, in known apparatus, the force generated by the solenoid is transmitted to the cam device through a ratchet mechanism, so that the solenoid must be comparatively powerful. A solenoid of such type is expensive and large in size, thereby creating disadvantages such as requiring a wider space in the tape player and considerably great power consumption.
The known apparatus may be thought to be advantageous, because an existing capstan flywheel is used. In a system of such type, the cam device is selectively engaged with the flywheel via a V-shaped lever, for example, in order to transmit the driving force of the flywheel to the cam device. More particularly, one arm of the lever is selectively engaged with a projection extending from the flywheel, while the other arm is selectively engaged with the ratchet wheel provided on the cam device and operated together with it. Thus, when both arms of the lever simultaneously engage the projection and the ratchet wheel, the projection, which rotates with the flywheel, operates the lever and the cam device thereby rotates via the ratchet wheel.
A comparatively small-sized solenoid, utilizing little power, is utilized in order to engage the lever with the projection and the ratchet wheel selectively. When the solenoid is energized, the lever moves and engages both members. If it is required to shift the magnetic tape head one track, the cam device must rotate at least 45.degree.. For this purpose, in such case, the rotating angle of the lever must be wider than 45.degree., and therefore a longer operating time is required for the lever. The longer operating time is liable to cause an error in the driving of the cam device; that is, in the shift operation of the tape head.
Furthermore, since they cross almost at right angles to each other when the lever engages the projection of the flywheel, and the flywheel is rotating at a comparatively high speed, the lever receives a comparatively large shock. This will also cause an error in the shift operation of the tape head. Moreover, since the cam device has a configuration which is such as to be rotated by receiving the rotating force of the capstan flywheel via the lever having a comparatively large rotating angle, it is necessary to provide a reasonable gap between the cam device and the flywheel. This restriction prevents the close positioning of the cam device and the flywheel. This is a serious disadvantage to a desired reduction in size of the apparatus.
An object of the invention is to provide apparatus for shifting the magnetic tape head in a multitrack tape player, which apparatus overcomes the disadvantages of the known apparatus.
Another object of the invention is to provide apparatus of reduced size for shifting the magnetic tape head in a multitrack tape player.
Still another object of the invention is to provide apparatus which functions efficiently, reliably, smoothly and without error in shift operation for shifting the magnetic tape head in a multitrack tape player.
Yet another object of the invention is to provide apparatus of reduced size, which is light in weight and inexpensive in manufacture and shifts the magnetic tape head in a multitrack tape player with very little probability of error.